1. Technical Field
The technical field relates to an interchangeable lens and a camera body which compose a camera system, and an intermediate lens mounted between the interchangeable lens and the camera body.
2. Related Art
For a camera system including an interchangeable lens and a camera body, there is known an intermediate lens mounted between the interchangeable lens and the camera body. By mounting the intermediate lens, for example, a focal length can be extended compared to that of the interchangeable lens alone (see, for example, JP59-188622A).
In a conventional intermediate lens, a group of lenses included in the intermediate lens is fixed within a lens barrel. Therefore, when the intermediate lens is mounted to a camera system, the camera system is limited in flexibility of control of an optical system included in the camera system. For example, when an intermediate lens with a magnification fixed to 2× (double) mounted to an interchangeable lens with a zoom magnification of 4× (four times), the zoom magnification of this combination is in a range equivalent to 2× to 8× (eight times) compared to that of the interchangeable lens alone. Namely, with the intermediate lens being mounted to the camera system, the zoom magnification cannot be set to a magnification of 1× (one time) and thus the intermediate lens needs to be removed temporarily. Hence, even if a user wants to shot an image at a magnification of 1×, the user cannot shot an image right away and thus usability is poor.